1. Field of the Invention
The present invention relates to an optical card recording/regenerating apparatus for performing at least either information recording or regenerating on an optical card, and a recording/regenerating method for an optical card recording/regenerating apparatus.
2. Description of the Related Art and Prior Art
Optical cards have storage capacities that are several thousands to several ten thousands times larger than those magnetic cards have. The optical card is, however, unrewritable like a WORM optical disk. Nevertheless, because of the large storage capacity ranging from 2 to 3 megabytes, the uses as a health care card or an equivalent for storing past data of an admission history and a prepaid card, as well as the application for customer administration are under consideration. Experiments have already been taken up in some fields of applications.
In an optical card recording/regenerating apparatus which has been put to use, an optical card is reciprocated along tracks on an optical card in order to perform at least either recording or regenerating.
U.S. patent application Ser. No. 07/786,654 filed by the present applicant has disclosed an example of an optical card recording/regenerating apparatus. In the prior art, an optical card is loaded on an optical card base, the optical card base is reciprocated with respect to an optical head, and thus recording or regenerating is achieved. The reciprocation is performed over the data existent between ID divisions at both edges of the optical card in such a manner that the relative speed of a light beam irradiated from the optical head with respect to the optical card held on the optical card base will be constant. When the light beam is outside the ID divisions of the optical card, the relative speed between the light beam and the optical card is accelerated or decelerated.
In the card recording/regenerating apparatus, information recorded in the ID divisions and data division must be read stably and accurately (or to be written in the data division). While a light beam is accessing the ID divisions and data division, the relative speed of an optical card with respect to the light beam must be constant. In a conventional apparatus, the drive speed for an optical card is increased to become constant by the time when a light beam comes to an outer end of one of ID divisions formed in the vicinities of the edges of the card. In other words, a drive unit including a motor for driving an optical card base, which holds an optical card, not only drives the optical card at a constant speed from an outer end of one ID division to an outer end of the other ID division, but also accelerates or decelerates the optical card outside the ends of the ID divisions.
The larger the drive length (range) becomes, the bigger the drive unit grows. This results in a large-scale optical card recording/regenerating apparatus. When a voice coil motor is employed as the drive unit, the motor itself becomes large in size. A long drive length leads to a large access time.
If the space between ID divisions is narrowed, the drive length decreases. This realizes downsizing of the apparatus. However, the quantity of information to be recorded diminishes accordingly. This idea is therefore unacceptable.
The same address is sometimes recorded multiple times in the ID divisions so that track address information can be read out correctly and reliably. In this method, however, if the space between ID divisions is narrowed, the number of addresses that can be recorded decreases. The reliability of reading an address deteriorates.
A method is available, wherein an access time is reduced by increasing a driving acceleration. In this method, the apparatus by itself generates terrible vibrations and is susceptible to external vibrations or shocks.